How Low to Spin??

Mark James Boyd wrote:
> Well, for now anyway, I can't see myself doing steep banks in the
> pattern. And since the FAA says so, I'm gonna teach no more than
> medium banks, and mild or moderate roll rates. At the recommended
> pattern size, I don't see why this isn't sufficient.

In my mind (for gliders), a shallow bank is anything less than 30
degrees, moderate/medium is 30 to 45, steep is 45 to 55, and from 55 on
up you're in aerobatic territory. I use moderate turns for patterns and
most thermals, and steep turns only when needed for thermals (almost
always down low). I simply reject the notion that one is in any way
"safer" by using shallow turns near the ground...

Marc

Bert Willing wrote:
> Don't get me wrong: I am very cautious close to the ground, even though I
> did extensive spin testing with my ship. I actually very often do not come
> to the conclusion that this or that low level IS safe, and then I don't do
> it.
> It's just statements like "never thermal below 400ft" which I don't like,
> although I agree that in many (maybe most) cases it would be unsafe. "Never"
> and "always" don't help people to practise actively thinking about every
> single situation they're in, and I think that it this lack of active
> situational awareness which is a main cause of fatal accidents.
> If you keep telling that "never below x feet", some will think "well my
> alti reads x+100ft, so I can safely thermal" - and that might be totally
> wrong for a special situation.
>
Hi Bert

In this case I am entirely in agreement - situational awareness and evaluation
of the possible outcomes is fundamental. The "I will never spin THIS plane
unintentionally so it is always safe" is equally dangerous to the "never thermal
below x feet rule"

Know your aircraft, evaluate the situation and the weather and make a reasoned
decision as to how much risk to take. This is OK, and some people will accept
different risk levels, and what is dangerous for a low timer may be safer for an
experienced pilot. Note I did not say safe - just safer. Flying gliders is
dangerous - accepting that and managing the risk is the key step to being safer.

There has to be some motivation to take risk though, and hubris is a poor
reason. The complications arise with objectivity - most people are less
objective about their own capabilities than they think (me included)

If you are low and in the circuit I still believe you should land unless there
is some hazard on the runway that increases the risk of landing above the risk
involved in thermalling low down, possibly below spin recovery height, where
there is the probability of conflicting traffic. Under pressure objectivity
tends to decrease - rather err on the side of caution, as you said.

To paraphrase a bumper sticker - A bad day retrieving beats a good day in hospital.

Bruce

Barb ,

Perhaps "routine" isn't the right word, as like you, it's not something I
see our fellow (local) pilots doing. I have however heard several of them
talk about contests where the only way to a particular turnpoint was to fly
a stretch with no known landing options from the top of the lift, and I
*have* heard at least a couple of them talk about "no option" situations
they knowingly entered. (There are parts of GW's flight from Turf to
Moriarty in April where I have no idea where he could have landed without
another thermal, and I recall him mentioning something to that effect in his
discussion of that remarkable flight.)

Of course, I've participated in only one sanctioned contest, so the
frequency that competitive pilots (not to be confused with me!) actually do
this, and how they handle it, is something I have to accept at face value
from other competitors.

-ted

"BMacLean" <bmaclean2@cox.net> wrote in message
news:zJMWc.60231$wo.50491@okepread06...
> I fly with the same group as you Ted and I wonder where you get the idea
> that it is "routine" to fly with no landing options, even in hardcore
> competition. I don't believe this to be the case and I agree with Eric.
I
> have found that when a pilot is relating a story of some scary situation
> they got themselves into and I ask them where they would have landed, 99%
of
> the time they have an answer.
>
> Barb
>
>

stant2@ (Kirk Stant) wrote in message

>Not the same as max performance low altitude turning (thermalling),
>which are definitely NOT ground reference maneuvers.

Thermalling close to the ground is not intended to be a ground
reference maneuver, but the visual feedback from the ground can have a
strong influence on control inputs. It is very important to keep
airspeed in the scan and not to be influenced by ground speed. The
input from ground reference can be very compelling, and misleading,
when thermalling low in a strong wind.

Andy

mjboyd@cats.ucsc.edu (Mark James Boyd) wrote in message news:<412e8424$1@darkstar>...

>
> We had this discussion before. If the thermal is coming from a
> stationary ground source, and the best performance is
> zero sink in the thermal, doing it exactly as a ground
> reference manuever (shallow upwind, steep tailwind) is correct.
>
> Otherwise one is blown downwind of the thermal.
>
> This was well discussed in threads about a year ago.
>
> If one starts at 60 degree banks on the upwind, with
> 10+ knots of wind and zero sink, trying to core the thermal
> on the downwind will be exciting...

Thermalling at any height is a thermal referenced maneuver. The
thermal is in the air, the maneuver is not ground referenced.

Visual inputs from changing ground speed must not be allowed to take
priority over airspeed control, and they will if you are not very
careful to keep airspeed in the scan.

Andy

Bruce Hoult wrote:
>
> In article <412F8938.87145612@inria.fr>,
> Robert Ehrlich <Robert.Ehrlich@inria.fr> wrote:
>
> > > Well, I disagree, and I strongly believe that a well-trained glider
> > > pilot, in any glider, low or high, should be every bit as comfortable
> > > and safe (if not more so) in a 50 degree bank as in a 20 degree bank.
> > >
> > > Marc
> >
> > Agreed for feeling safe, but when comfortable is the question, I think
> > most pilots would find 1.02g is much more comfortable than 1.75g.
>
> That's 1.06 vs 1.56, actually.
>

I agree, some mistyping probably in my previous calculation.